Unsquashed commit -- Changes as requested:

- Rebase master (Now all unit tests pass)

- Fix seanbright review issue: ast_var_set problems
 Resolution: Turns out that it's not so simple to just overwrite the
 existing string.  Best option is to just remove and add like everyone else

 Resolves: Memory overwrite when overwriting existing group variable
 with larger string

include/asterisk/chanvars.h

@@ -63,21 +63,6 @@ struct ast_var_t *_ast_var_assign(const char *name, const char *value, const cha
  */
 #define ast_var_assign(name, value) _ast_var_assign(name, value, __FILE__, __LINE__, __PRETTY_FUNCTION__)
 
-/*!
- * \brief Replace the value of an existing variable
- * \pre Caller assumes all responsibility for handling locking
- *
- * \see ast_var_find
- * \see ast_var_assign
- *
- * \param var           must be a struct ast_var_t * that's been set up with ast_var_assign
- * \param new_value     value of the variable to set
- *
- * \retval 1
- * \retval 0 on success
- */
-int ast_var_set(const struct ast_var_t *var, const char *new_value);
-
 /*!
  * \brief Free a variable.  This does not remove the variable from the list that it might be a part of
  * \see linkedlists.h

main/app.c

@@ -2463,9 +2463,8 @@ int ast_app_group_set_var(struct ast_channel *chan, const char *group, const cha
 	struct ast_group_meta *gmi = NULL;
 
 	struct varshead *headp;
-	struct ast_var_t *newvariable = NULL;
-	int existing_var_found = 0;
-
+	struct ast_var_t *variable = NULL;
+	
 	if (!group || !name) {
 		ast_log(LOG_WARNING, "<%s> GROUP variable assignment failed for %s@%s, group/name cannot be NULL, group variable '%s' not set\n", ast_channel_name(chan), group, category, name);
 		return -2;
@@ -2488,22 +2487,17 @@ int ast_app_group_set_var(struct ast_channel *chan, const char *group, const cha
 
 		headp = &gmi->varshead;
 
-		AST_LIST_TRAVERSE(headp, newvariable, entries) {
-			if (strcasecmp(ast_var_name(newvariable), name) == 0) {
-				/* there is already such a variable, replace it */
-				existing_var_found = 1;
-				ast_var_set(newvariable, value);
+		AST_LIST_TRAVERSE(headp, variable, entries) {
+			if (strcasecmp(ast_var_name(variable), name) == 0) {
+				/* there is already such a variable, nuke it so we can replace it */
+				ast_var_delete(variable);
 				break;
 			}
 		}
 
-		if (existing_var_found) {
-			break;
-		}
-
-		newvariable = ast_var_assign(name, value);
+		variable = ast_var_assign(name, value);
 
-		AST_LIST_INSERT_HEAD(headp, newvariable, entries);
+		AST_LIST_INSERT_HEAD(headp, variable, entries);
 		manager_event(EVENT_FLAG_DIALPLAN, "GroupVarSet",
 			"Channel: %s\r\n"
 			"Category: %s\r\n"
@@ -2520,7 +2514,7 @@ int ast_app_group_set_var(struct ast_channel *chan, const char *group, const cha
 	AST_RWLIST_TRAVERSE_SAFE_END;
 	AST_RWLIST_UNLOCK(&groups_meta);
 
-	if (!newvariable) {
+	if (!variable) {
 		ast_log(LOG_WARNING, "<%s> GROUP assignment %s@%s doesn't exist, group variable '%s' not set\n", ast_channel_name(chan), group, category, name);
 		return -1;
 	}

main/chanvars.c

@@ -52,13 +52,6 @@ struct ast_var_t *_ast_var_assign(const char *name, const char *value, const cha
 	return var;
 }
 
-int ast_var_set(const struct ast_var_t *var, const char *new_value)
-{
-	ast_copy_string(var->value, new_value, strlen(new_value));
-
-	return 0;
-}
-
 void ast_var_delete(struct ast_var_t *var)
 {
 	ast_free(var);